1. General Model Information

Name: TREe GROwth: Response of Plants to Interacting Stresses

Acronym: TREGRO

Main medium: terrestrial
Main subject: biogeochemistry
Organization level: organism, ecosystem
Type of model: not specified
Main application:
Keywords: tree,soil,physiology, ozone stress, air pollution, water stress, nutrient deficiencies


David Weinstein

The Boyce Thompson Institute for Plant Research
Cornell University Ithaca
NY 14853
Phone: (607) 254-1228
Email: David Weinstein

Robert Goldstein

Electric Power Research Institute
3412 Hillview Avenue
Palo Alto
CA 94304
Fax (A.) 607-254-1242



The simulation model, TREGRO, has been developed at the Boyce Thompson Institute from funds supplied by the Electric Power Research Institute to analyze the response of trees to multiple environmental stresses. TREGRO simulates the plant's ability to utilize resources to fix carbon in photosynthesis, the allocation patterns used to maintain carbon fixation and nutrient and water uptake, and the plant's ability to repair pollution damage. The TREGRO model can aid in evaluating long term effects of pollution on resource availability, potential for gradual deterioration of tree health under long periods of pollution exposure, and imbalances in growth accompanying shifts in carbon allocation.

TREGRO predicts growth and patterns of carbon allocation expected for an isolated tree exposed to various levels of ozone, nutrient stress, and water availability. The tree is divided into the following compartments: buds, a canopy consisting of up to ten leaf year classes, branches, stem, and a fine and coarse root pool in each of three soil layers. The model calculates the photosynthesis of the entire tree each hour as a function of ambient environmental conditions and the availability of light, water, and nutrients. To accomplish this task, the model keeps track of the the availability of light, water, and nutrient resources needed for the fixation process, the quantity of essential nutrients and water available in each soil horizon and the amount of these resources taken up by the tree, and the amounts of these nutrient resources and fixed carbon available and used to build the component tissues of the plant, and the flow of carbon used to manufacture leaf tissue. The model predicts the growth of the tree over periods ranging from one hour (the basic model time step) to many years. The model was designed to be readily applicable to predicting the growth dynamics of most tree species, and has been used to simulate both coniferous and deciduous trees.

Author of the abstract:

Plant Modeling Group : Environmental Biology Program at Boyce Thompson Institute

II. Technical Information

II.1 Executables:

Operating System(s): TREGRO runs on Macintosh personal computers equipped with systems software version 6.0.5 or later, 2 MB RAM and 3 MB free hard disk storage.

II.2 Source-code:

Programming Language(s): FORTRAN TREGRO might be obtained from the Electric Power Software Center, San Diego.

II.3 Manuals:

II.4 Data:

III. Mathematical Information

III.1 Mathematics

A pre-publication draft about
by E. Shewliakowa, H. Dowlatabadi, M.J. Small -Department of Engineering & Public Policy Carnegie Mellon University Pittsburgh, PA 15213, USA might be downloaded here (as pdf-file).

III.2 Quantities

III.2.1 Input

III.2.2 Output

IV. References

Samuelson, L. J., M. A. Arthur, D. A. Weinstein, and G. S. Edwards. 1994.
Simulating the growth of northern red oak seedlings and mature trees in response to ozone using TREGRO. Abstract in Bulletin of the Ecological Society of America. 75 (2): 203.

Weinstein, D. A., and R. D. Yanai. 1994.
Integrating the effects of simultaneous multiple stresses on plants using the simulation model TREGRO. J. Environ. Qual. 23:418-428.

Weinstein, D. A., R. M. Beloin, R. D. Yanai, C. G. Zollweg, and B. Gollands.In review. TREGRO simulation model of the carbon, water, and nutrient balances of a plant-soil system. Model Version 3.0. Model description and Parameter Requirements. Electric Power Research Institute. Research Project 2799-1.

Weinstein, D. A., R. M. Beloin, R. D. Yanai, C. G. Zollweg. 1992.
TREGRO simulation model of the carbon, water, and nutrient balances of a plant-soil system. Volume 1: Model Version 1.74 Description and Parameter Requirements. Electric Power Research Institute. Research Project 2799-1.

V. Further information in the World-Wide-Web

VI. Additional remarks

Last review of this document by: October, 19th 1997 M.Sonntag
Status of the document:
last modified by Tobias Gabele Wed Aug 21 21:44:51 CEST 2002

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